Index: llvm/include/llvm/ProfileData/InstrProf.h
===================================================================
--- llvm/include/llvm/ProfileData/InstrProf.h
+++ llvm/include/llvm/ProfileData/InstrProf.h
@@ -1143,8 +1143,8 @@
// Create a COMDAT variable INSTR_PROF_RAW_VERSION_VAR to make the runtime
// aware this is an ir_level profile so it can set the version flag.
-void createIRLevelProfileFlagVar(Module &M, bool IsCS,
- bool InstrEntryBBEnabled);
+GlobalVariable *createIRLevelProfileFlagVar(Module &M, bool IsCS,
+ bool InstrEntryBBEnabled);
// Create the variable for the profile file name.
void createProfileFileNameVar(Module &M, StringRef InstrProfileOutput);
Index: llvm/lib/ProfileData/InstrProf.cpp
===================================================================
--- llvm/lib/ProfileData/InstrProf.cpp
+++ llvm/lib/ProfileData/InstrProf.cpp
@@ -1098,10 +1098,14 @@
bool isIRPGOFlagSet(const Module *M) {
auto IRInstrVar =
M->getNamedGlobal(INSTR_PROF_QUOTE(INSTR_PROF_RAW_VERSION_VAR));
- if (!IRInstrVar || IRInstrVar->isDeclaration() ||
- IRInstrVar->hasLocalLinkage())
+ if (!IRInstrVar || IRInstrVar->hasLocalLinkage())
return false;
+ // For CSPGO+LTO, this variable might be marked as non-prevailing and we only
+ // have the decl.
+ if (IRInstrVar->isDeclaration())
+ return true;
+
// Check if the flag is set.
if (!IRInstrVar->hasInitializer())
return false;
@@ -1137,8 +1141,8 @@
// Create a COMDAT variable INSTR_PROF_RAW_VERSION_VAR to make the runtime
// aware this is an ir_level profile so it can set the version flag.
-void createIRLevelProfileFlagVar(Module &M, bool IsCS,
- bool InstrEntryBBEnabled) {
+GlobalVariable *createIRLevelProfileFlagVar(Module &M, bool IsCS,
+ bool InstrEntryBBEnabled) {
const StringRef VarName(INSTR_PROF_QUOTE(INSTR_PROF_RAW_VERSION_VAR));
Type *IntTy64 = Type::getInt64Ty(M.getContext());
uint64_t ProfileVersion = (INSTR_PROF_RAW_VERSION | VARIANT_MASK_IR_PROF);
@@ -1155,6 +1159,7 @@
IRLevelVersionVariable->setLinkage(GlobalValue::ExternalLinkage);
IRLevelVersionVariable->setComdat(M.getOrInsertComdat(VarName));
}
+ return IRLevelVersionVariable;
}
// Create the variable for the profile file name.
Index: llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
===================================================================
--- llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
+++ llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
@@ -110,6 +110,7 @@
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Instrumentation.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Transforms/Utils/ModuleUtils.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
@@ -464,7 +465,10 @@
private:
bool runOnModule(Module &M) override {
createProfileFileNameVar(M, InstrProfileOutput);
- createIRLevelProfileFlagVar(M, /* IsCS */ true, PGOInstrumentEntry);
+ // The variable in a comdat may be discarded by LTO. Ensure the
+ // declaration will be retained.
+ appendToCompilerUsed(
+ M, createIRLevelProfileFlagVar(M, /*IsCS=*/true, PGOInstrumentEntry));
return false;
}
std::string InstrProfileOutput;
@@ -1612,7 +1616,7 @@
// For the context-sensitve instrumentation, we should have a separated pass
// (before LTO/ThinLTO linking) to create these variables.
if (!IsCS)
- createIRLevelProfileFlagVar(M, /* IsCS */ false, PGOInstrumentEntry);
+ createIRLevelProfileFlagVar(M, /*IsCS=*/false, PGOInstrumentEntry);
std::unordered_multimap<Comdat *, GlobalValue *> ComdatMembers;
collectComdatMembers(M, ComdatMembers);
@@ -1632,7 +1636,10 @@
PreservedAnalyses
PGOInstrumentationGenCreateVar::run(Module &M, ModuleAnalysisManager &AM) {
createProfileFileNameVar(M, CSInstrName);
- createIRLevelProfileFlagVar(M, /* IsCS */ true, PGOInstrumentEntry);
+ // The variable in a comdat may be discarded by LTO. Ensure the declaration
+ // will be retained.
+ appendToCompilerUsed(
+ M, createIRLevelProfileFlagVar(M, /*IsCS=*/true, PGOInstrumentEntry));
return PreservedAnalyses::all();
}
Index: llvm/test/Transforms/PGOProfile/Inputs/thinlto_cspgo_bar_gen.ll
===================================================================
--- llvm/test/Transforms/PGOProfile/Inputs/thinlto_cspgo_bar_gen.ll
+++ llvm/test/Transforms/PGOProfile/Inputs/thinlto_cspgo_bar_gen.ll
@@ -1,13 +1,8 @@
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
-$__llvm_profile_filename = comdat any
-$__llvm_profile_raw_version = comdat any
-
@odd = common dso_local global i32 0, align 4
@even = common dso_local global i32 0, align 4
-@__llvm_profile_filename = constant [25 x i8] c"pass2/default_%m.profraw\00", comdat
-@__llvm_profile_raw_version = constant i64 216172782113783812, comdat
define dso_local void @bar(i32 %n) !prof !29 {
entry:
Index: llvm/test/Transforms/PGOProfile/lto_cspgo_gen.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/PGOProfile/lto_cspgo_gen.ll
@@ -0,0 +1,32 @@
+; REQUIRES: x86-registered-target
+
+; RUN: opt -passes='thinlto-pre-link<O2>' --cs-profilegen-file=alloc -cspgo-kind=cspgo-instr-gen-pipeline -module-summary %s -o %t.bc
+; RUN: llvm-dis %t.bc -o - | FileCheck %s --check-prefix=IRPGOPRE
+
+;; Symbol __llvm_profile_filename and __llvm_profile_raw_version are non-prevailing here.
+; RUN: llvm-lto2 run -lto-cspgo-profile-file=alloc -lto-cspgo-gen -save-temps -o %t %t.bc \
+; RUN: -r=%t.bc,f,px \
+; RUN: -r=%t.bc,__llvm_profile_filename,x \
+; RUN: -r=%t.bc,__llvm_profile_raw_version,x
+; RUN: llvm-dis %t.0.0.preopt.bc -o - | FileCheck %s --check-prefix=IRPGOBE
+
+;; Before LTO, we should have the __llvm_profile_raw_version definition.
+; IRPGOPRE: @__llvm_profile_raw_version = constant i64
+
+;; Non-prevailing __llvm_profile_raw_version is discarded by LTO. Ensure the
+;; declaration is retained.
+; IRPGOBE: @__llvm_profile_raw_version = external constant i64
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+$f = comdat any
+
+; Function Attrs: nofree norecurse nosync nounwind readnone uwtable willreturn mustprogress
+define i32 @f() {
+entry:
+ ret i32 1
+}
+
+!llvm.module.flags = !{!0}
+!0 = !{i32 1, !"ThinLTO", i32 0}
Index: llvm/test/Transforms/PGOProfile/thinlto_cspgo_gen.ll
===================================================================
--- llvm/test/Transforms/PGOProfile/thinlto_cspgo_gen.ll
+++ llvm/test/Transforms/PGOProfile/thinlto_cspgo_gen.ll
@@ -1,7 +1,7 @@
; REQUIRES: x86-registered-target
-; RUN: opt -module-summary %s -o %t1.bc
-; RUN: opt -module-summary %S/Inputs/thinlto_cspgo_bar_gen.ll -o %t2.bc
+; RUN: opt -passes='thinlto-pre-link<O2>' --cs-profilegen-file=alloc -cspgo-kind=cspgo-instr-gen-pipeline -module-summary %s -o %t1.bc
+; RUN: opt -passes='thinlto-pre-link<O2>' --cs-profilegen-file=alloc -cspgo-kind=cspgo-instr-gen-pipeline -module-summary %S/Inputs/thinlto_cspgo_bar_gen.ll -o %t2.bc
; RUN: llvm-lto2 run -lto-cspgo-profile-file=alloc -lto-cspgo-gen -save-temps -o %t %t1.bc %t2.bc \
; RUN: -r=%t1.bc,foo,pl \
; RUN: -r=%t1.bc,bar,l \
@@ -13,8 +13,15 @@
; RUN: -r=%t2.bc,even,pl \
; RUN: -r=%t2.bc,__llvm_profile_filename,x \
; RUN: -r=%t2.bc,__llvm_profile_raw_version,x
-; RUN: llvm-dis %t.1.4.opt.bc -o - | FileCheck %s --check-prefix=CSGEN
+; RUN: llvm-dis %t.1.4.opt.bc -o - | FileCheck %s --check-prefixes=CSGEN,PREVAILING
+; RUN: llvm-dis %t.2.4.opt.bc -o - | FileCheck %s --check-prefixes=CSGEN,NOPREVAILING
+;; Prevailing __llvm_profile_raw_version is kept by LTO.
+; PREVAILING: @__llvm_profile_raw_version = constant i64
+
+;; Non-prevailing __llvm_profile_raw_version is discarded by LTO. Ensure the
+;; declaration is retained.
+; NOPREVAILING: @__llvm_profile_raw_version = external constant i64
; CSGEN: @__profc_
; CSGEN: @__profd_
@@ -22,11 +29,6 @@
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
-$__llvm_profile_filename = comdat any
-$__llvm_profile_raw_version = comdat any
-@__llvm_profile_filename = constant [25 x i8] c"pass2/default_%m.profraw\00", comdat
-@__llvm_profile_raw_version = constant i64 216172782113783812, comdat
-
define dso_local void @foo() #0 !prof !29 {
entry:
br label %for.body